With their three other Asian restaurants well ensconced on the Main Line, Sutida and Win Somboonsong might view Teikoku, their first foray into Chester County, as the jewel of a budding empire.

After all, teikoku means "empire" in Japanese. And this is a restaurant that looks the part. Set on the crest of a rolling Newtown Square hill and ringed by a vast parking lot crammed with Land Rovers, Jaguars and Porsches, Teikoku resembles a Japanese shrine trimmed with luminous lanterns and a sprawling wooden porch that turns fragrant in the summer rain.

Inside, water trickles down a chain wall of metal cups that leads to a moody dining room punctuated by more lanterns and plantation fans suspended from tall rafters. A polished crowd of young people sip ginger martinis as they nibble volcano rolls and lobster dumplings at the bar.

It's quite the update for a former biker bar that later morphed into Bobby's Seafood, a long-standing fish house noted for the sawed-off boat that sat out front. But the Somboonsongs, who also own the Thai Pepper restaurants in Ardmore and Wayne and Mikado in Ardmore, spent millions of dollars on this property and its renovation, and it shows.

Teikoku also has one of the best cellars I've seen at a local Asian restaurant, with a smart selection of eclectic wines (from an Austrian gruner veltliner to Oregon pinot noirs), a superb list of cold sakes, and surprising attention to good beers, including a creamy Lion stout from Thailand featured recently as a special.

Fine-tuning the pan-Asian cuisine and the service, however, has been more of a challenge.

Thai-Japanese-influenced Teikoku is one of several upscale suburban Asia-plexes to open in recent years, grafting Japanese sushi bars onto kitchens that approach Chinese, Thai or Korean cuisine with varying degrees of authenticity. The trick, of course, is to strike a balance between traditional dishes and trendier fusion flavors without seeming to pander to the largely non-Asian clientele.

Teikoku has improved in this regard since opening last year, taking more creative risks and becoming more assertive in its seasonings. But the kitchen still struggles with inconsistency.

The sushi can be wonderful, with exquisite ingredients such as delicate saltwater eel, buttery toro tuna, sweet shrimp, tender surf clams, and seared white albacore tuna tataki splashed with citrusy ponzu sauce. An unusual zuke special brings slices of sake-cured big-eye tuna basking in a pungent green oil with herbs and wasabi.

But sometimes the sushi bar tends toward gimmickry and carelessness. The volcano roll is little more than a mound of California rolls drowned in lava flows of spicy mayo. The flaming dragon roll is overwhelmed by the Sterno-like odor of the high-octane rum used to flambe it tableside.

Other rolls are too loosely built, with gaps between the rice and centers that allow ingredients to fall out. My tempura lobster tail toppled out of its rice wrapper before it got to my table.

The non-sushi kitchen, led by Morimoto veteran Gregory McColgan, was up and down, too. McColgan knows how to let good ingredients speak for themselves. The best example is the Kobe beef appetizer, which brings nearly a quarter pound of thinly sliced raw rib-eye alongside a blazing-hot square of polished black granite. Diners can sear the meat themselves (they usually do it too long - it takes only seconds to cook) and dunk it into a delicate ponzu sauce before savoring the luxurious beef. At $20, it's pricey but worth it, especially to share.

Good Black Angus beef saves the sukiyaki, a classic Japanese dish served in a handsome, cast-iron pot stuffed with mushrooms, chewy shirataki (yam-paste noodles), silken tofu, and rich, sake-tinged veal broth.

Succulent grilled scallops highlight an entree of snappy edamame with lightly truffled, heavily sweetened teriyaki sauce. Stir-fried rice jeweled with lumps of crab and vibrating with fresh chile spice and minty Thai basil is another surprising find.

Yet high-quality ingredients didn't always ensure success. A lobster dumpling appetizer was sweet with the crimson crustacean one night, but fishy and pale on another. Large ravioli stuffed with wild mushrooms were burned to a bitter crisp around the edges.

An ample portion of Chilean sea bass looked intriguing with its flavorful garnish of shiitake mushrooms and gingery soybeans, but the fish was chewy and overcooked. The seafood green curry practically overflowed with mussels, shrimp, scallops and calamari. But it, too, was marred by overcooking and by its bed of mushy linguine. It also was surprisingly bland, considering that it was billed as "very spicy."

The phyllo-wrapped shrimp, an entree I've tasted at several other pan-Asian restaurants, came with a nice sweet and spicy satay sauce. But the big shrimps were wound so tightly that the textural explosion of the shredded phyllo - the whole point of the dish - was dulled.

Teikoku offers a three-course chef's tasting menu that would be a bargain at $29, but the wonderful first course (meaty lamb chops encrusted with Tasmanian pepper) was followed by a dud (two tiny fried soft-shell crabs that tasted as if they were burned in tired oil).

The most frustrating aspect of the tasting meal, though, was that it threw my companions' a la carte meals for a loop. My entree had been delivered nearly 20 minutes before our pleasant but scattered waitress realized that my guests had ordered entrees, too. (We reminded her.) Fifteen minutes later, their food finally arrived - with an explanation that a wine dinner had interrupted all orders in the main dining room for half an hour.

Upscale restaurants organize winemaker dinners when they aspire to greatness, an appealing extra like those hard-to-find ingredients, fine sakes and sleek decor.

But it is the everyday details that are the foundation of a great restaurant empire. And Teikoku has a few to refine before it achieves that status in more than name and promise only.

Contact restaurant critic Craig LaBan at 215-854-2682 or claban@phillynews.com. Read his recent work at http://go.philly.com/craiglaban.